JP2013022171A - Catheter type photoacoustic probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly scan an ultrasonic detector in the front direction while preventing the invasion of a liquid causing the scattering of light from the outside in a catheter type photoacoustic probe.SOLUTION: An external sheath 31 is inserted in a lumen. The inside of the external sheath 31 is filled with a liquid and an internal sheath 32 is movable in the external sheath 31 along the extending direction of the lumen. The ultrasonic detector 21 and a light irradiation part constituted, for example, of a lens 22 and a mirror 23 are arranged in the internal sheath 32. The external sheath 31 has filters 24 and 25 for filtering the liquid present outside the external sheath 31.

Description

  The present invention relates to a catheter-type photoacoustic probe, and more particularly to a catheter-type photoacoustic probe that is inserted into a lumen and detects a photoacoustic signal in the lumen.

  An ultrasonic inspection method is known as a kind of image inspection method capable of non-invasively examining the state inside a living body. In the ultrasonic inspection, an ultrasonic probe capable of transmitting and receiving ultrasonic waves is used. When ultrasonic waves are transmitted from the ultrasonic probe to the subject (living body), the ultrasonic waves travel inside the living body and are reflected at the tissue interface. By receiving the reflected sound wave with the ultrasonic probe and calculating the distance based on the time until the reflected ultrasonic wave returns to the ultrasonic probe, the internal state can be imaged.

  In addition, photoacoustic imaging is known in which the inside of a living body is imaged using a photoacoustic effect. In general, in photoacoustic imaging, a living body is irradiated with pulsed laser light such as a laser pulse. Inside the living body, for example, living tissue absorbs the energy of pulsed laser light, and ultrasonic waves (photoacoustic signals) are generated by adiabatic expansion due to the energy. By detecting this photoacoustic signal with an ultrasonic probe or the like and constructing a photoacoustic image based on the detection signal, in-vivo visualization based on the photoacoustic signal is possible.

  Here, Patent Document 1 describes a catheter-type ultrasonic probe that is used by being inserted into a blood vessel or the like. A catheter tube inserted into a blood vessel is filled with a liquid such as physiological saline. A rotating wire is inserted into the catheter tube, and an ultrasonic transducer is attached to the tip of the rotating wire. By rotating the ultrasonic transducer in the catheter tube with the rotating wire, the ultrasonic beam can be scanned radially.

  The reason why the catheter tube is filled with the liquid is to ensure ultrasonic propagation. If bubbles exist around the ultrasonic transducer, the ultrasonic waves are scattered and reflected by the bubbles, and the image quality of the ultrasonic image deteriorates. As a measure for eliminating bubbles, it is conceivable to provide an opening at the tip of the catheter tube and push the bubbles out of the catheter tube. However, in this case, blood or the like can enter the catheter tube from the outside through the opening, which is not preferable.

  With respect to the above problem, in Patent Document 1, the distal end portion of the catheter tube is configured by a member having gas permeability and liquid non-passability. By doing in this way, it is possible to prevent blood and the like from entering the catheter tube from the outside while allowing air bubbles to be driven out of the catheter tube.

JP 2000-126184 A

  The catheter-type photoacoustic probe also needs to be filled with a liquid in order to ensure the propagation of the photoacoustic signal. By providing an opening at the end of the tube, air bubbles in the tube can be expelled, but blood enters the tube through the opening, and the infiltrated blood scatters or absorbs light to be irradiated on the observation target. As a result, there is a possibility that sufficient intensity of light cannot be applied to the observation target. On the other hand, as in Patent Document 1, when a gas-permeable member and a liquid non-transparent member are used, the penetration of the liquid into the tube is completely blocked. In this case, when the ultrasonic transducer (ultrasonic detector) is scanned in the forward direction, the ultrasonic transducer may not be scanned smoothly.

  In view of the above, the present invention provides a catheter-type photoacoustic probe capable of smoothly scanning an ultrasonic detector forward while removing bubbles and preventing intrusion of liquid that causes light scattering from the outside. The purpose is to do.

  In order to achieve the above object, a catheter-type photoacoustic probe of the present invention is inserted into a lumen, and the inside is filled with a liquid, and the inside of the outer sheath moves in the direction in which the lumen extends. A possible inner sheath, a light irradiation unit disposed in the inner sheath, and an ultrasonic detector, wherein the outer sheath has a filter for filtering liquid existing outside the outer sheath. A catheter-type photoacoustic probe is provided.

  In the catheter-type photoacoustic probe of the present invention, the filter may be provided near the distal end of the outer sheath. The number of filters provided near the tip is not limited to one, and a plurality of filters may be provided.

  When the lumen is a blood vessel, it is preferable that the filter filters at least red blood cells in blood. In other words, it is preferable that the filter can remove at least red blood cells from the blood entering from the outside to the inside of the outer sheath.

  The filter may be a ultrafiltration membrane. The ultrafiltration membrane can be a polysulfone membrane. It is preferable that the polysulfone membrane is attached so that the pressure side faces the outside of the outer sheath.

  Instead of the above, the filter may be a porous membrane.

  The inner sheath can scan in the radial direction within the outer sheath.

  The present invention also detects a photoacoustic signal generated by a light source unit that emits light to be irradiated on the subject and a light absorber that is inserted into the lumen and absorbs the light. A catheter-type photoacoustic probe, and an ultrasonic unit that generates a photoacoustic image based on the detected photoacoustic signal, and the catheter-type photoacoustic probe is inserted into a lumen, An outer sheath filled with a liquid, an inner sheath movable in the outer sheath in the direction of extension of the lumen, a light irradiation unit disposed in the inner sheath, and an ultrasonic detector, A photoacoustic image generating apparatus is provided in which the outer sheath has a filter for filtering liquid existing outside the outer sheath.

  In the catheter-type photoacoustic probe of the present invention, the outer sheath that movably houses the inner sheath in the interior filled with the liquid has a filter that filters the liquid such as blood existing outside the outer sheath. . With this filter, bubbles existing in the liquid in the outer sheath can be driven out of the outer sheath. In addition, the filter partially restricts the movement of the liquid between the outside and the inside of the outer sheath, so that substances that cause light scattering in the liquid existing outside the outside sheath can be inside the outside sheath. Intrusion can be prevented. At this time, since the liquid flow is not completely blocked, the inner sheath can be smoothly moved forward in the outer sheath.

1 is a block diagram showing a photoacoustic image generation apparatus according to an embodiment of the present invention. Sectional drawing which shows the catheter type photoacoustic probe of one Embodiment of this invention. Sectional drawing which shows the state which moved the inner sheath in the catheter type photoacoustic probe.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a photoacoustic image generation apparatus according to an embodiment of the present invention. The photoacoustic image generation apparatus 10 includes an ultrasonic probe 11, an ultrasonic unit 12, and a laser unit 13. The laser unit 13 emits light to be irradiated on the subject. What is necessary is just to set the wavelength of the emitted laser beam suitably according to an observation object. The laser beam emitted from the laser unit 13 is guided to the ultrasonic probe 11 through the optical fiber 14.

  The ultrasonic probe 11 is a catheter-type photoacoustic probe inserted into a lumen such as blood. The ultrasonic probe 11 irradiates the subject with the laser light guided from the laser unit 13. The ultrasonic probe 11 detects a photoacoustic signal generated by absorbing the laser beam irradiated by the light absorber in the subject.

  The ultrasonic unit 12 is connected to the ultrasonic probe 11 by a cable 15 and receives a photoacoustic signal detected by the ultrasonic probe 11. The ultrasonic unit 12 generates a photoacoustic image based on the received photoacoustic signal. For example, the ultrasonic unit 12 displays the generated photoacoustic signal on a display monitor.

  FIG. 2 shows a cross section of the ultrasonic probe 11. The ultrasonic probe 11 includes an outer sheath 31 and an inner sheath 32. The outer sheath 31 is inserted into a lumen such as a blood vessel. The inside of the outer sheath 31 is filled with a liquid such as physiological saline. The outer diameter of the inner sheath 32 is smaller than the inner diameter of the outer sheath 31, and the outer sheath 31 accommodates the inner sheath 32 therein. The inner sheath 32 is configured to be movable in the outer sheath 31 along the extending direction of the lumen. Further, the inner sheath 32 is rotatable in the radial direction within the outer sheath.

  The inner sheath 32 accommodates the optical fiber 14, the lens 22, the mirror 23, the ultrasonic detector 21, and the window 26 therein. The lens 22 and the mirror 23 constitute a light irradiation unit that irradiates the subject with light. The lens 22 enlarges the diameter of the laser light guided using the optical fiber 14 and emits the laser light toward the mirror 23. The mirror 23 reflects the laser beam toward the subject. The configuration of the light irradiation unit is arbitrary and is not limited to the combination of the lens 22 and the mirror 23.

  The window 26 is formed of a member having optical transparency and ultrasonic transmission. The light reflected by the mirror 23 is irradiated to the subject through the window 26. In the subject, a photoacoustic signal is generated by absorbing the laser beam irradiated by the light absorber. The ultrasonic detector 21 receives a photoacoustic signal from within the subject via the window 26.

  Outside the outer sheath 31, there is a liquid, for example blood, present in the lumen. The outer sheath 31 includes filters 24 and 25 that filter liquid existing outside the outer sheath. For example, the outer sheath 31 has filters 24 and 25 in the vicinity of the tip (distal end) of the outer sheath 31. The filters 24 and 25 filter, for example, red blood cells in blood and substances having a size equal to or larger than that. In other words, the filters 24 and 25 do not pass red blood cells and substances having a size equal to or larger than that, but allow other components or gases in the blood to pass through.

  The filters 24 and 25 are, for example, ultrafiltration membranes. Polysulfone membranes can be used for the filters 24 and 25. The polysulfone membrane is attached so that the pressure side faces the outside of the outer sheath 31. Alternatively, a porous membrane can be used for the filters 24 and 25 instead. Note that. The filters 24 and 25 may be the same type of filter, or may be different types of filters. Further, it is not necessary to provide two filters, and only one of the two filters 24 and 25 may be provided.

  FIG. 3 shows a state in which the inner sheath 32 is moved to the front side. Assume that the inner sheath 32 is pulled to the near side from the position shown in FIG. 2 manually or using some drive means. At that time, a negative pressure is generated at the distal end portion of the outer sheath 31 as the inner sheath 32 moves. If an opening for removing bubbles is provided at the distal end of the outer sheath 31, blood enters the outer sheath 31 due to the negative pressure. In particular, since red blood cells cause light scattering, it is desired to prevent red blood cells from entering the outer sheath 31. In the present embodiment, the filters 24 and 25 are provided in the vicinity of the distal end of the outer sheath 31. By filtering, for example, red blood cells using these filters, it is possible to prevent red blood cells from entering the outer sheath 31. On the other hand, although red blood cells and substances having a size equal to or larger than that are removed, other components are allowed to enter the outer sheath 31, so that the inner sheath 32 can be smoothly moved forward. .

  In the above embodiment, the photoacoustic signal is detected by the ultrasonic probe 11 and the photoacoustic image is generated by the ultrasonic unit. However, the ultrasonic wave is transmitted to and received from the subject. The unit may generate an ultrasonic image in addition to the generation of the photoacoustic image. That is, the ultrasonic detector 11 of the ultrasonic probe 11 transmits ultrasonic waves to the subject, detects reflected ultrasonic waves with respect to the ultrasonic waves transmitted by the ultrasonic detector 21, and the ultrasonic unit 12 The detected reflected ultrasound may be received from the ultrasound probe 11 and an ultrasound image may be generated based on the received reflected ultrasound. For example, the ultrasonic unit 12 can synthesize or arrange the generated photoacoustic signal and ultrasonic signal and display them on the display monitor.

  As mentioned above, although this invention was demonstrated based on the suitable embodiment, the probe for catheter type photoacoustics of this invention is not limited only to the said embodiment, Various correction | amendment and the structure from the said embodiment are carried out. Changes are also included in the scope of the present invention.

10: Photoacoustic image generation apparatus 11: Ultrasonic probe 12: Ultrasonic unit 13: Laser unit 14: Optical fiber 15: Cable 21: Ultrasonic detector 22: Lens 23: Mirror 24, 25: Filter 26: Window 31: Outer sheath 32: Inner sheath

Claims (9)

An outer sheath that is inserted into the lumen and filled with liquid;
An inner sheath movable within the outer sheath in the direction of extension of the lumen;
A light irradiation unit disposed in the inner sheath, and an ultrasonic detector,
The catheter-type photoacoustic probe, wherein the outer sheath has a filter for filtering liquid existing outside the outer sheath.   2. The catheter-type photoacoustic probe according to claim 1, wherein the filter is provided near the tip of the outer sheath.   The catheter-type photoacoustic probe according to claim 1 or 2, wherein the lumen is a blood vessel, and the filter filters at least red blood cells in blood.   The catheter type photoacoustic probe according to any one of claims 1 to 3, wherein the filter is a ultrafiltration membrane.   The catheter type photoacoustic probe according to claim 4, wherein the ultrafiltration membrane is a polysulfone membrane.   6. The catheter-type photoacoustic probe according to claim 5, wherein the polysulfone membrane is attached such that the pressure side faces the outside of the outer sheath.   The catheter type photoacoustic probe according to any one of claims 1 to 3, wherein the filter is a porous membrane.   The catheter type photoacoustic probe according to any one of claims 1 to 7, wherein the inner sheath is capable of scanning the outer sheath in a radial direction. A light source unit that emits light to be irradiated to the subject;
A catheter-type photoacoustic probe that is inserted into a lumen and detects a photoacoustic signal generated when the light absorber in the subject absorbs the light;
An ultrasonic unit that generates a photoacoustic image based on the detected photoacoustic signal,
The catheter-type photoacoustic probe is inserted into a lumen and the inside is filled with a liquid; an inner sheath that is movable in the extending direction of the lumen in the outer sheath; and A photoacoustic image generation apparatus comprising: a light irradiation unit disposed therein; and an ultrasonic detector, wherein the outer sheath includes a filter for filtering liquid existing outside the outer sheath.

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